Disable web applet and warning when compiling for Linux on CI

yuzu's web applet does not or barely reacts to user input while open in
Linux. It can be closed via 'Exit Web Applet' on the menubar, however if
yuzu is in fullscreen, this is effectively a softlock as the menubar
cannot be accessed.

This disables building yuzu with the web applet on the Linux CI target.
In addition, this disables the QMessageBox warning about not having
compiled yuzu with the web applet.

.ci/scripts/linux/docker.sh

@@ -5,7 +5,7 @@ cd /yuzu
 ccache -s
 
 mkdir build || true && cd build
-cmake .. -G Ninja -DDISPLAY_VERSION=$1 -DYUZU_USE_BUNDLED_UNICORN=ON -DYUZU_USE_QT_WEB_ENGINE=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=/usr/lib/ccache/gcc -DCMAKE_CXX_COMPILER=/usr/lib/ccache/g++ -DYUZU_ENABLE_COMPATIBILITY_REPORTING=${ENABLE_COMPATIBILITY_REPORTING:-"OFF"} -DENABLE_COMPATIBILITY_LIST_DOWNLOAD=ON -DUSE_DISCORD_PRESENCE=ON -DENABLE_QT_TRANSLATION=ON
+cmake .. -G Ninja -DDISPLAY_VERSION=$1 -DYUZU_USE_BUNDLED_UNICORN=ON -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=/usr/lib/ccache/gcc -DCMAKE_CXX_COMPILER=/usr/lib/ccache/g++ -DYUZU_ENABLE_COMPATIBILITY_REPORTING=${ENABLE_COMPATIBILITY_REPORTING:-"OFF"} -DENABLE_COMPATIBILITY_LIST_DOWNLOAD=ON -DUSE_DISCORD_PRESENCE=ON -DENABLE_QT_TRANSLATION=ON
 
 ninja
 

src/yuzu/main.cpp

@@ -477,11 +477,13 @@ void GMainWindow::WebBrowserOpenPage(std::string_view filename, std::string_view
 #else
 
 void GMainWindow::WebBrowserOpenPage(std::string_view filename, std::string_view additional_args) {
+#ifndef __linux__
     QMessageBox::warning(
         this, tr("Web Applet"),
         tr("This version of yuzu was built without QtWebEngine support, meaning that yuzu cannot "
            "properly display the game manual or web page requested."),
         QMessageBox::Ok, QMessageBox::Ok);
+#endif
 
     LOG_INFO(Frontend,
              "(STUBBED) called - Missing QtWebEngine dependency needed to open website page at "